The present invention relates to a filling technology capable of effective elimination of gap in microstructure array.
The microlens is an essential component part of optical and optoelectronic products. For example, the microlens is used as a light condenser at the end of optical fiber, or as a focusing means of optical scanner. In addition, the microlens is used to construct the microlens array of display. Moreover, the microlens is used as a light condenser of micro-optic integrated element. The conventional process of making a microlens array is incapable of eliminating microgap of the microlens array. The microgap undermines the resolution of the product.
The Taiwan Pat. Series No. 89122015 discloses a batch process for fabricating microlens array. The process is described hereinafter with reference to FIG. 1. The process involves a first step in which a substrate 100 is coated with a polyimide composite layer 210 and a photomask composite layer 220. The coated substrate 100 is then patterned by lithography, thereby resulting in formation of a bottom layer of the polyimide composite 210 and a plurality of top layers of photomask composite 220, as shown in FIG. 1B and FIG. 1C. The patterned substrate 100 is heated subsequently at a temperature ranging between 180xc2x0 C. and 220xc2x0 C., so as to bring about reflow. In the meantime, the photomask layer 220 has transformed into a microlens 230 due to equilibrium of cohesive force and surface tension, as shown in FIG. 1D. In light of transformation of microlens array by reflow, the coated substrate 100 is patterned at intervals by lithography, so as to prevent the reflow overlapping phenomenon in the course of the reflow. As a result, there are gaps in the microlens array. The gaps undermine the resolution of the microlens array. The gaps of the microlens array may be eliminated by a presision mechanical process, a photomask process, or laser process. However, these processes are neither cost-effective nor efficient.
The primary objective of the present invention is to provide a filling technology capable of effective elimination of gaps in a microstructure array, thereby resulting in enhancement of resolution of the microstructure array.
It is another objective of the present invention to provide a process for fabricating a non-gap microstructure array in high density so as to reduce effectively the unit ares.
It is still another objective of the present invention to provide a simple and cost-effective process for fabricating microstructure arrays of various forms.